In some lighting environments, such as in the application of light supplementing lamp for plants, the light supplementing lamp is usually suspended above the plant and remains a fixed distance from the plant. In this case, if the distance is too short, the plant may be burned by the light, while if the distance is too long, the loss of light increases, and accordingly the plant may not receive sufficient light. In this regard, with plant growth, the suspension height of the light supplementing lamp frequently needs to be adjusted higher. Moreover, when a season of crop growth or a growth cycle of the plant is over, the light supplementing lamp needs to be re-adjusted down to its initial height when new crop or plant growth begins. At present, the light supplementing lamps available on the market are all the lamps fixedly suspended on indoor ceilings, which cannot be easily adjusted corresponding to plant height, which may result in wasting a lot of resources. Therefore, how to achieve a simple adjustment on the height of a suspended lamp becomes a problem to be solved.
The patent document CN104334967A discloses a device for suspending and adjusting the height of a lamp. Although the device is able to increase the height of the lamp by way of pulling a cord to drive a limiting member to rotate, it is unable to drive the limiting member to rotate reversely so as to reduce the height of the lamp. Thus, this device is very inconvenient in actual use. In light of the foregoing, in order to easily adjust the height of a suspended lamp, a control member needs to be created to act on the limiting member, such that the limiting member can be driven to rotate reversely to reduce the height of the suspended lamp.